The Nile and ancient Egypt

Hail to thee, O Nile! Who manifests thyself over this land, and comes to give life to Egypt! Mysterious is thy issuing forth from the darkness, on this day whereon it is celebrated! Watering the orchards created by Re, to cause all the cattle to live, you give the earth to drink, inexhaustible one! Path that descends from the sky, loving the bread of Seb and the first-fruits of Nepera, You cause the workshops of Ptah to prosper!

Without the Nile there would certainly not have been the Egypt we know, nor without the almost complete desertification of northern Africa [1] from the sixth to the fourth millennia BCE.
The savannas had always been just about capable of sustaining small groups of hunter gatherers and herders, who had never had the surpluses necessary to create a high culture producing great architecture and art. When the people fleeing the spreading deserts joined those who had been living along the Nile all the time, they formed a large sized population of hundreds of thousands, which was a prerequisite for the flourishing of this new culture dependent on significant masses of labourers.
For as long as there were nomadic peoples roaming the lands surrounding Egypt, the Nile continued to attract them in times of hardship. Many never left its banks again and were absorbed into the general population. But once these neighbouring peoples had settled down, they rarely abandoned their landed properties despite frequent occurrences of drought; and the influx of civilian populations greatly decreased.

The area inhabited included the Delta apart from the marshes, the Fayum around Lake Moeris, a strip of land along the Nile up to the first cataract at Aswan, never exceeding 25 km in width, but often much narrower and a few oases in the Western Desert, a few tens of thousands square kilometres of irrigated and thus habitable land. [17]

The Nile is with a length of 6,650 km the longest river in the world, its catchment area is huge, more than 3 million square kilometres with a mean annual rainfall of about 600 mm at present, yet its average discharge is with less than 3,000 m³/s among the smallest of the great rivers. A large part of the water the Nile carries originates in Ethiopia and is due to the summer monsoons. The rest comes from as far south as Rwanda. This central African region has two rainy seasons, one in spring the other in autumn. A number of huge lakes serve as reservoirs, evening out the flow of the White Nile. [2]

Every year the level of the Nile began to rise in the summer, covering the floodplain. But when it failed to rise enough or when it rose too much [15], it caused hardship even during the most prosperous periods. And when the climatic disturbances in the Nile's catchment area were prolonged, the whole fabric of society might fall apart:

Inscription near Kumma giving the height of the riverSource: Oriental Institute of the University of Chicago

11500 BCE: 500 years of excessive flooding caused the abandonment of early attempts at agriculture and a return to a nomadic existence of fishing, hunting and gathering [22] until the end of the 6th millennium.

3000-2800: The decline in the flooding of about 1 to 1.5m, ca. 30% of the flow, was followed by widespread unrest and the depopulation of Nubia.[19]

1840-1770: High inundations [20] weakened the central power of the Middle Kingdom dynasties, which was exploited by the Hyksos to take over large parts of Egypt.

1170-1100: Low inundations [21] accompanied the decline of the New Kingdom.

Much more frequent than these catastrophic events were minor fluctuation in the maximal floodlevels, when just the farmers working marginal land were affected; but for these it could mean the end of the dream of a secure existence. In February 221 CE a certain Lucius Nonius Cassianus asked the strategos of the Fayum for a cancellation of his tenancy contract for eleven aruras of wheatland, writing:

...I have paid the rent in its entirety until last year; but this year the aruras have remained out of reach of the flood waters because of the insufficiency of the inundation, I cannot take upon myself to cultivate them anymore. I thus present this request and ask that a copy be addressed to Isidora (the landlady) to let her know that I am leaving the rented land. I have already proven to her by witnesses that it is not through a fault of mine that the land has dried out...

After Henne 1927

Given the importance of the Nile flooding [9] and its regular returns, it is no wonder that the Egyptians began measuring the rise probably even before historic times in order to predict the harvest. At first these records were little more than marks on the river bank, but later marked stairs, pillars or wells were built and records of the measurements kept. The most important nilometer lay on the island of Elephantine, others were built at different times at Philae, Edfu, Khenu, Memphis, Heliopolis, Buto and other places [4].
The Palermo stone, carved towards the end of the 5th dynasty, lists the kings and adds the most outstanding events of their reigns such as processions, festivals, and wars, and included records of the level of the Nile. The highest surviving recorded height was 8 cubits 3 fingers (4¼ metres), the lowest 1 cubit (½ metre) and the average about 4 cubits (2 metres).
When one compares the data one often assumes that the units, the place of measurement, the depth of the river bed, and the way of measuring remained the same over the centuries, an assumption not necessarily correct. According to Herodotus a rise of 8 cubits (4 metres) covered the whole of Egypt during the Middle Kingdom [14] while from the Late Period on a rise of sixteen cubits was measured during the height of inundation:

They said that when Moeris was king, the Nile overflowed all Egypt below Memphis, as soon as it rose so little as eight cubits. Now Moeris had not been dead 900 years at the time when I heard this of the priests; yet at the present day, unless the river rise sixteen, or, at the very least, fifteen cubits, it does not overflow the lands.

Herodotus Euterpe translated by George Rawlinson, [2.13.1]

Diagram of the rise of the Nile at Wadi Halfa in a normal year during the early 20th century CE.After L.Casson, Ancient Egypt, p.34

A footnote in Beloes' translation of Herodotus [11] mentions that during the Roman occupation Trajan struck a medal which attests to a height of 16 cubits (8 metres), under Julian a height of 15 cubits (7½ metres) was recorded, and in modern times (before the damming of the Nile of course) a height of eight metres was considered to be plentiful. He also gives 24 cubits (12 metres) as the highest recorded rise of the Nile. The lowest Nile on record is dated by Martineau [13] to the year 966 CE and amounted to six and a half metres. Budge wrote in 1885 that a rise of 25 to 26½ feet (about 8 to 9 metres) was enough to water the whole country in modern times [12].Taharka recorded an inundation of the unprecedented height of 21 cubits, 1 handbreadth, 2½ fingers at the quai of Thebes,[18] after he had implored Amen-Re for a flood...to prevent drought in his time, and which may have caused quite a bit of havoc, though that is not recorded on his stela. The following harvest appears to have been especially bountiful:

It (i.e. the flood) made the entire harvest good for me, for it killed the rats and the snakes therein and prevented the locust from devouring it and the south wind from reaping it.

Equally as important as the amount of the water was its burden – the silt it carried from the highlands of Ethiopia and deposited along its slow-flowing lower course [5]. It turned the colour of the earth black, fertilized it, retained moisture better than the red earth of the surrounding desert, and prevented the degradation of the soil through salinization, which elsewhere turned many artificially irrigated areas into deserts. In the Delta formerly marshy areas were slowly covered with soil suitable for agriculture. The land was thus extended by some twenty to thirty kilometres during the reign of the pharaohs.
Natural levees were formed of the coarser matter deposited by the river and were in many places above the normal levels of the inundation. They were the logical locations for the foundation of settlements, close to the mud used for building habitations, the clay deposits for making pottery, the water needed for drinking, irrigation and transportation, with its fish feeding the people, and yet relatively safe during inundation. These elevations rose higher over the millennia, when houses built of adobe collapsed and new ones were built on top of the debris. Abandoned locations on the other hand slowly disappeared into the surrounding countryside which was continually rising.

The course of the river changed over time and moved steadily further east at an average rate of about two to three metres a year. Towns followed this movement: land became available as the riverbed shifted, and new houses were built along the riverfront, while the old ones decaying on the western edge of the town were not rebuilt. More permanent structures built of stone such as temples, were in danger of losing their easy access to their main supply route. Worse, if they were erected on low ground they might be flooded and even be finally engulfed by the Nile waters as the land rose and with it the river.

The second cataractPicture source: Oriental Institute, University of Chicago

At the cataracts, obstacles to river shipping, where - unless navigable canals were cut through the granite and maintained - ships were unloaded and the freight was carried overland, towns were built where the cargo could be stored and guarded, and slipways were constructed for dragging the ships overland.
The first cataract just south of Aswan was considered the natural southern frontier of the country, until Nubia was conquered and a string of fortresses built along the river up to the second cataract which was guarded by the fortifications of Semna and Kumma.

The fauna and flora in and along the river were more varied in ancient times than they are today, when much of the floodplain is given over to agriculture. There were never any dense forests with straight-stemmed high growing trees suitable for the building of ships and habitations, but there were copses of palm trees, sycamores and the like while the hardier acacia could grow at the edges of the desert. Shrubbery and grasses covered much of the ground, and in the swampy parts of the delta reeds abounded.

The large wild animals living in the Nile, the hippos and crocodiles, or farther afield, the lions and ostriches [6] were hunted and their habitats destroyed. Smaller animals were less endangered and some like rats and mice positively flourished. But much of the wild life disappeared and was replaced by domesticated cattle, pigs, sheep, goats and donkeys.

For a long time the Egyptians did not know anything about the origins of their river, nor about the monsoon rains far away which caused it to rise and water their land,[16] nor about the reasons for the continued fertility of their soil. All this remained mysterious to them, but they were aware of their dependence on the river and tried to make sure it would continue to sustain them by deifying and worshiping it. To them the river was Hapi who had the shape of a well-nourished, bearded, blue man with pendulous breasts [10].

It is the form of the Nile, one half of which is a man, the other half a woman.

Memphite cosmogonic text After a German translation in Lurker 1998, p.91

Hapi was a dual deity: As the god of the Upper Nile Hap-Reset he wore a crown of lotus flowers, as Hap-Meht, the Lower Egyptian god, he was adorned with papyrus[3]. Hapi, the rising Nile, was the father nourishing the nation. Keeping him contented was one of the main duties of the pharaoh. But despite the esteem he enjoyed, there was no major permanent Hapi cult.
Other gods were invoked when disaster threatened the inhabitants of the Nile Valley

Year 3, first month of the second season, day 12, under the majesty of the King of Upper and Lower Egypt, Lord of the Two Lands, Usermare-Setepnamon, L.P.H.; Son of Re, Lord of the diadems, Osorkon (II) Siese-Meriamon, given life forever.
The flood came on, in this whole land; it invaded the two shores as in the beginning. This land was in his power like the sea, there was no dyke of the people to withstand its fury. All the people were like birds upon its [...], the tempest ... his ....., suspended ..... ..... like the heavens. All the temples of Thebes were like marshes.
On this day Amon caused to appear in Opet, the [barque] of his (portable) image ....; when he entered the "Great House" of his barque in his temple.

Flood inscription at Karnak22nd dynastyBreasted part IV §743

Picture sources:
[ ] The insert in the floodplain map is an excerpt taken from Silverman, David P. Ancient Egypt 1997
[ ] Source of the photograph excerpts of Kumma and the second cataract: Oriental Institute of the University of Chicago website
[ ] The photograph of Hapi courtesy Jon Bodsworth.

Footnotes:[1] Annual rainfall nowadays averages less than 50 mm in Egypt except for the coastal region with 100 to 200 mm. It was slightly higher in ancient times.[3] The plants symbolizing Upper and Lower Egypt respectively[5] The depth of the alluvial deposits is four metres at Aswan, 9.6 metres in the Cairo region and even greater in the Delta. [6] The ostrich survived in Egypt until the beginning of the 20th century.[7] Lonnie Thompson, professor of geological sciences at Ohio State found a layer containing dust in a 4000 year old ice core taken from Mount Kilimandjaro [8][9] This importance was reflected in religion. The flooding and the subsequent emergence of the land was an annual replay of the original act of creation in which the pharaoh played a role.

(Life to) The son of Re Sebekhotpe, beloved of the great inundation, given/giver of life for ever. Year 4, fourth month of Smw, the epagomenal days, under the auspices of the person of this god, living for ever. His person went to the hall of this temple <in order to> see the great inundation. His person came <to> the hall of the temple which was full of water. [Then his person] waded there .....

13th dynasty
Baines 1974, p.40

The onset of the inundation was also the beginning of the agricultural year, which was the base of the Egyptian calendar. But by setting the year's length to 365 days, the calendar year became independent of the agricultural year, and New Year's Day wandered through all the seasons.[10] It has been suggested that Hapi had female breasts, symbolizing his role as nourisher of the country, but there are no depictions of Hapi breastfeeding. Others think that his is a case of gynecomastia.[11]Herodotus, tr. by W.Beloe, Jones & Co. London, 1831, footnote on p.69[12] Budge, 1978, p.109.[13] Martineau 1848, p.231[14] Herodotus does not give any location. For comparison: a graffiti at Kumma in lower Nubia above the second cataract records an inundation height of 1.83 m during the late 12th dynasty (Ian Shaw 2000, p.170)[15] At times even Niles which were too high gave rise to celebrations. Temples represented the first created land emerging from the primordial waters. The 13th dynasty pharaoh Sobekhotep VIII was tickled pink when he could re-enact in his flooded Karnak temple the act of the creator god: he waded through the floodwaters and - timing his appearance correctly to the very peak of the inundation - he probably ordered the waters to recede and saw them obey him, and then had the incident carved into stone for posterity. (Baines 1974, pp. 39-54.)
But a particularly destructive inundation during the reign of Osorkon III made them think of the waters of chaos:

Nun came forth ... [and covered] this land to its limits. It stretched to the two borders (of the land) as in the first time ... this land was given to its power as (to) the sea.

elSebaie 2000, p.30

[16] By the 7th century BCE the Egyptians appear to have had a better understanding of the matter. A 26th dynasty stela seems to make a connection between the rains in the far South, referred to as Punt, and the rising Nile:

...rainfall upon the mountain of Punt ... this month in which its rain was, (when) it was not the season (for it), even in the Delta towns; your mother, (the goddess) Neith, has brought it for you - a Nile flood to sustain your forces

T. Shaw, Andah, Sinclair 2001, p.602

[17] In 1880 CE the total land under cultivation was estimated to amount to 25,000 square kilometres, and one may suppose that the cultivated area in antiquity did not exceed this amount. (Aperghis 2004, p.56)[18] Assmann 2002 p.358ff.[19] Butzer 1976, p.28[20] Butzer 1976, p. 29[21] Butzer 1976, p. 56[22] Butzer 1976, p. 9